#include <stdio.h>
unsigned long int fact (int m);
int main (void)
{
    int n;
    unsigned long int g;
    double one_over_nfactorial;
    scanf ("%d", &n);
    g = fact (n);
    one_over_nfactorial = 1. / g;
    printf ("1/%d! = %e", n, one_over_nfactorial);
    return (0);
}
unsigned long int fact(int m)
{
    int i;
    unsigned long int product;
    product = 1;
    for (i=m; i>=1; i--)
    {
        product *= i;
    }
    return (product);
}

